How to do music match?

I've read that Xbox Music can scan your music library and match albums that they have licenses to and make them available for streaming on any of your devices. Is that true? If so, how do you initiate it? And does it work with music on an external drive?

I have all my music on a usb hard drive. I connected it to my Surface Pro 3 and told Xbox Music to look at that drive for music to add to my "Collection." A few minutes later it had scanned the drive and found metadata for the majority of my albums. Now I see my entire collection in Xbox Music on my Surface, but there is no indication that any of them are being matched and made available for streaming. I've logged into Xbox Music on another PC and my collection is still empty.

Sadly they just removed this feature in favour of using onedrve for your music

If you now want to see your collection on all your devices you need to upload it to onedrive

Sigh. I really don't want to upload all my music to OneDrive. Matching would have been so much more convenient. Oh well. Not a big deal. I use Slacker Radio for streaming on my devices so Xbox Music isn't that important to me. I just thought music matching would be a good reason to start using it